In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the TDS message decoder in the Vert.x MSSQL client (vertx-mssql-client) aggregates inbound TDS packets into a composite direct-memory buffer without any cumulative size limit. A malicious, compromised, or man-in-the-middle SQL Server can send a continuous stream of TDS packets without setting the END_OF_MESSAGE status flag, causing unbounded direct-memory allocation on the client and leading to an out-of-memory crash. This occurs before authentication completes.
The impacted component is io.vertx:vertx-mssql-client.